1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR> 4 ; This program and the accompanying materials 5 ; are licensed and made available under the terms and conditions of the BSD License 6 ; which accompanies this distribution. The full text of the license may be found at 7 ; http://opensource.org/licenses/bsd-license.php 8 ; 9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ; Module Name: 13 ; 14 ; CopyMem.asm 15 ; 16 ; Abstract: 17 ; 18 ; memcpy function 19 ; 20 ; Notes: 21 ; 22 ;------------------------------------------------------------------------------ 23 24 .686 25 .model flat,C 26 .mmx 27 .code 28 29 ;------------------------------------------------------------------------------ 30 ; VOID * 31 ; memcpy ( 32 ; IN VOID *Destination, 33 ; IN VOID *Source, 34 ; IN UINTN Count 35 ; ); 36 ;------------------------------------------------------------------------------ 37 memcpy PROC USES esi edi 38 mov esi, [esp + 16] ; esi <- Source 39 mov edi, [esp + 12] ; edi <- Destination 40 mov edx, [esp + 20] ; edx <- Count 41 lea eax, [esi + edx - 1] ; eax <- End of Source 42 cmp esi, edi 43 je @CopyMemDone 44 cmp edx, 0 45 je @CopyMemDone 46 cmp esi, edi 47 jae @F 48 cmp eax, edi ; Overlapped? 49 jae @CopyBackward ; Copy backward if overlapped 50 @@: 51 mov ecx, edx 52 and edx, 7 53 shr ecx, 3 ; ecx <- # of Qwords to copy 54 jz @CopyBytes 55 push eax 56 push eax 57 movq [esp], mm0 ; save mm0 58 @@: 59 movq mm0, [esi] 60 movq [edi], mm0 61 add esi, 8 62 add edi, 8 63 loop @B 64 movq mm0, [esp] ; restore mm0 65 pop ecx ; stack cleanup 66 pop ecx ; stack cleanup 67 jmp @CopyBytes 68 @CopyBackward: 69 mov esi, eax ; esi <- Last byte in Source 70 lea edi, [edi + edx - 1] ; edi <- Last byte in Destination 71 std 72 @CopyBytes: 73 mov ecx, edx 74 rep movsb 75 cld 76 @CopyMemDone: 77 mov eax, [esp + 12] 78 ret 79 memcpy ENDP 80 81 END 82